Make sure you have connected to the right pin and that there is a really a variable voltage there (with a multi-meter). You might even just use a pot instead of your switch array or whatever it is to simplify things.
If your reading varies a little then I'd guess you are actually getting an ADC value. If it's stuck at exactly 0 you might not be using the right software for the converter. See some examples in the demo apps or in the sensorboards code. Also make sure you are reading the right ADC channel. MS PETTA NICOLO' wrote: > Good morning, > > I have a problem with TelosB ADC input. > > I need reading four different values on ADC input. So I use a selector > that switches over a voltage divider powered by the Analog VCC (pin 1 of > the 10-pin expansion connector) and closed over the Analog Ground (pin 9 > of the 10-pin expansion connector). The output of the selector represent > the ADC’s input. > > > > I know that the input impedance of ADC is 1 MΩ. > > I use 1 KΩ resistors to make the divider, but I find the ADC input > voltage is always about 0 Volt, as if it is grounded. > > > > Can someone tell me why it doesn’t work correctly? Where do I make mistake? > > I am at your disposal for further clarifications. > > > > Thank you very much for your attention. > > > > > > ---------------------------------------------------------------- > **Nicolò Petta****** > > ** ** > > **Infomobility ** > > /Technologies Department/ > > Strada Torino 50, 10043 Orbassano (TO), Italy > Phone:+39 0119080530 Fax:+39 0119083083 > e-mail: [email protected] <mailto:[email protected]> > web site: www.crf.it <http://www.crf.it> > ---------------------------------------------------------------- > > ----------Internet E-Mail confidentiality > footer------------------------------------------------- > The information transmitted in this e-mail message is intended only for > the person or entity to which it is addressed and may contain > confidential information.Any retransmission, dissemination or other use > of, or taking of any action in reliance upon, this information by person > or entity other than the intended recipient, if not clearly authorized > by the sender, is prohibited.If you have received this communication in > error, please notify the sender immediately by e-mail and delete the > message from any computer. > > > > > > > ------------------------------------------------------------------------ > > _______________________________________________ > Tinyos-help mailing list > [email protected] > https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help -- Platform: WinXP/Cygwin TinyOS version: 1.x, Boomerang Programmer: MIB510 Device(s): Mica2, MicaZ, Tmote Sensor board: homebrew _______________________________________________ Tinyos-help mailing list [email protected] https://www.millennium.berkeley.edu/cgi-bin/mailman/listinfo/tinyos-help
